Hydraulic jacks

ABSTRACT

A hydraulic jack wherein the ram is moved in the ram cylinder by a selection of two or more pump pistons of different crosssectional area whereby higher or lower pressures with consequent slower or faster movement of the ram can be selected at will, as the operating handle of the pump piston is actuated.

United States Patent [191 Wride [111 3,806,091 Apr. 23, 1974 HYDRAULICJACKS [76] Inventor: Donald C. Wride, 35 Helen Ter.,

Valley View, Australia 5093 [22] Filed: Aug. 8, 1972 [21] Appl. No.:278,766

30 Foreign Application Priority Data Aug. 12, 1971 Australia 5872/71[52] US. Cl 254/93 R, 60/482, 60/479 [51] Int. Cl 1366f 3/24 [58] Fieldof Search 254/93 R, 93 A, 93 M;

[5 6] References Cited UNITED STATES PATENTS 7 2,824,424 2/1958 Sebenick254/93 R 2,434,296 l/1948 Swanson 417/487 Bivans 417/487 2,466,8154/1949 Lightburn 60/482 2,535,759 12/1950 Schwantner 254/93 M FOREIGNPATENTS OR APPLICATIONS 591,358 4/1925 France 60/482 PrimaryExaminer0thell M/Simpson Assistant Examiner-Robert C. Watson Attorney,Agent, or Firm-Oldham & Oldham [5 7] ABSTRACT A hydraulic jack whereinthe ram is moved in the ram cylinder by a selection of two or more pumppistons of different cross-sectional area whereby higher or lowerpressures with consequent slower or faster movement of the ram can beselected at will, as the operating handle of the. pump piston isactuated.

8 Claims, 4 Drawing Figures PATENTEB m 2 3 i974 sum 3 [1F 3 1 HYDRAULICJACKS BACKGROUND OF INVENTION This invention relates to improvements inand to bydraulic jacks.

It is customary in hydraulic jacks to utilize a pump of relatively smallcross-sectional area which is actuated by means of a hand lever to forcehydraulic fluid beneath a ram, which lifts the vehicle or the like forwhich purpose the jack has been designed, and to' provide with such adevice a mechanism which can be operated, such as by twisting a handleor release, whereby the ram can be lowered after repairs to the vehicleor the like have been completed.

Jacks of this nature are relatively slow acting because of the need toutilize a number of pumping strokes to achieve the necessary raisingwhile maintaining the pressures such that a heavy vehicle or the likecan be lifted without the exertion of too great a force. It is thisfactor which makes the jacking relatively slow.

SUMMARY OF INVENTION The object of the present invention is to providean improved form of jack in which light loads can be quickly raised butnevertheless to allow the greater pressures to be generated for liftingheavy loads.

It is a further object of the invention to provide a simple andeffective release for a jack which can be actuated without the necessityof difficult manoeuvres such as reaching beneath the vehicle or the liketo manipulate mechanism to allow the jack to be lowered.

A further object is to allow operation of the jack from various angles.I

The objects of the present invention are achieved by utilizing multiplepistons so arranged that depending on the stroke of the actuating leverthe required rate of movement can be achieved while release of thedevice is preferably simplified by so arranging the release mechanismthat an inward movement on the lever will release the fluid to lower thejack.

It will be realised that the invention can be constructed in variousways but to enable its nature to be fully appreciated an embodiment willnow be described but it is to be clear that the invention need notnecessarily be limited to this.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of a jackaccording to the invention,

FIG. 2 is a transverse section of same,

FIG. 3 is a view of a modified pump, and

FIG. 4 is a section on line 44 of FIG. 2.

The base 1 of the jack has on it a housing 2 which forms the containerfor the hydraulic fluid and within the housing is mounted the hydraulicram cylinder 3 and the ram 4 by means of which lifting is effected. Theusual screwed adjuster 5 is used to take up slack before commencing tolift.

The means for generating the pressure comprise a relatively smalldiameter piston 6 which can be reciprocated in the hollow of a largerdiameter piston 7 by being connected to a handle coupling member 8,which has on it a fulcrum member 9 engageable in slots 10 in the housing2. A pin 11 on the piston 6 engages a slot 12 in the handle couplingmember 8 to allow the fulcrum member 9 to be engaged in any one of thearcuate slots 10 on the housing 2.

The smaller diameter piston 6, which is the high pressure piston, iscoaxially arranged in relation to the larger diameter, or low pressurepiston 7 and the piston 6 is so disposed therein that by extendedmovement of the handle 14 which is inserted in the socket of thecoupling member 8 when the device is to be actuated, the smallerdiameter piston 6 can move in the larger diameter piston 7 which isnormally loaded by a spring 15 into a raised position.

The larger diameter piston 7 is disposed in a cylinder 16 whichcommunicates on the one hand through a one way valve 17 and duct 18 withthe housing 2 in which the fluid is held, and on the other hand througha one way valve 19 and duct 20 with the ram cylinder 3 of the hydraulicram 4.

The larger diameter piston 7 is hollow and has an aperture 22 so thatwhile its hollow communicates with the smaller diameter piston 6, thetwo pistons are so arranged that when the handle 14 is operated to bringthe smaller diameter piston 6 into contact with the larger diameterpiston 7 it closes off the aperture 22 in the larger diameter piston 7and moves the larger diameter piston downwardly against the pressure ofthe spring 15 to displace -a relative large quantity of the hydraulicfluid into the pressure chamber 3 and thus gives rapid lifting of theram 4 within this chamber.

Thus according to the device outlined, if the handle 14 is operatedduring say the lower half of its stroke it will directly operate thelarger diameter piston 7 through the smaller diameter piston 6 and willgive a quick action, but correspondingly lower lifting power, butimmediately the ram 4 has reached a position where greater force isrequired to move it, the larger diameter piston 7 is allowed to returnto its upper position against the stop 24 under action of the spring 15and by appropriately then operating the handle 14 at a higher part ofits stroke, the smaller diameter piston 6 only will be reciprocated,drawing the fluid from the housing 2 into the space below the largerdiameter piston 7 but through the hollow of the piston and the aperture22 into the hollow in the upper part of the larger diameter piston whichthen acts as the cylinder for the smaller diameter piston. By thenpumping the smaller diameter piston it will be realised .that because ofthe lower area a much more powerful lift is obtainable.

Both pistons will of course be provided with the usual seals such asO-rings 25.

The ram cylinder 3 is associated with a release valve 27 whichpreferably operates as .follows.

Disposed adjacent to the hollow of the handle coupling member 8 in whichthe handle 14 is engaged is a button 28 which is in line with the handle14 and is outwardly loaded by a spring 29. The button 28 forms part of atapered release member 30 engaged in a socket 31 in the housing 2. A rod32 is moved down when the button 28 is depressed and pushes the releasevalve 27 to 30 is held in the position where the ball valve 27 is closedunder normal conditions but when the handle 14, by means of which thedevice is actuated, is pushed further into the handle socket, itcontacts the button 28 and forces this release member back to operatethe lever to release the release valve and allow the ram to retract. Thehandle 14 can simply be pushed axially, or can have a thread 35 so thatby turning the handle it moves axially by having the thread engage ascrew 36 which can however be withdrawn out of engagement with thethread to allow axial movement of the handle 14 without rotation.

Normally, the end of the handle 14 is clear of the button 28 and has nocontact with the release member, but

when it is desired to lower the hydraulic jack it is only necessary topush the handle 14 further into the socket of the coupling member 8whereupon its end will contact the button 28 and will force it back intoa position where, through the connection to the release valve 27, thevalve will be actuated.

While in the foregoing the two pistons 6 and 7 have been described ascoaxially arranged it will be obvious that they can be otherwisearranged, and for instance three pistons could be used as shown in FIG.3 where the piston 40 is the smallest diameter piston and anintermediate piston 41 is positioned in an expanded bore" while-a largerpiston 42 is disposed in a still larger part of the bore.

In this case the bore 43 has a step 44 and a step 45, a strong spring 46normally holding the piston 42 against the step 45 while a weaker spring47 holds the piston 41 against the shoulder 44.

The pistons 4l and 42 have axial ducts through them, but the piston 40has an end 50 which seals the duct 51 when the piston'40 is forced down,and in turn the duct 52 of the piston 42 is engaged by a seat 53 on thepiston 41 to seal the piston 41 to the piston 42 when the piston 41 isforced down on to the piston 42.

To operate the device shown in FIG. 3, if high pressure is to begenerated in the mastercylinder 3 to actuate the lifting ram 4, thesmaller piston 40is reciprocated in a position where the end 50 does notclose the opening 51 through the'piston 41 and the reciprocation of thepiston 40 then draws oil from the housing and pumps it into the mastercylinder, the oil flowing through the duct 51 and the duct 52 in theother two pistons without having any effect on the pistons.

Asthe piston 40 is the smallest diameter piston, it generates arelatively high pressure and is therefore used to exert the greatestforce on the ram 4.

If a faster movement at a medium pressure is required the piston 40 isbrought down until the end 50 seals the duct 51 within the piston 41 andthe piston 40 is actuated in a somewhat lower position so that now thepiston 40 does not leave the piston 41 but operates in the medium sizedbore which is the position between the shoulder 44 and 45.

If a still quicker movement is required, the piston 40 is pushed downfurther until the end 53 of the piston 41 engages and seals on thepiston 42, and now if the piston 40 is actuated downwardly from thisposition, all three pistons. will move as a unit, but the spaces between the pistons will b'eisolated because the piston 42 has its duct 52now sealed to the duct 51 by the projection 53 on the piston 41 whilethe duct 51 in the piston 41 is sealed by the end 50 of the piston 40,so that now pumping takes place by movement of the piston 42 between theupper limit which is the shoulder 45 and the bottom of the bore of thelargest part of the cylinder.

As stated, the spring 47 is lighter than the spring 46, so that duringoperation of the intermediate piston 41 the piston 42 will beheldagainst the shoulder 45 but when further pressure is exerted to overcomethe pressure of the spring 47, the piston 41 seals to the piston 42 andactuation is then against the pressure of the spring 46.

To allow the jack to operate in any position, that is upright or lyingdown, the duct 18 in the base 1 has on it a nipple 60 to which isattached a flexible tube 61 the free end of which has on it a weight inthe form of a ball 62, the ball having through it an opening 63 withwhich the tube 61 communicates so that when the jack is in To allow theoperating handle 14 to be actuated from.

any one of a number of positions, the fulcrum member 9 can engage anyone of the arcuate slots 10, this being achieved by pulling back thehandle socket'8 on the pin 11, which is permitted because of the slot 12in the handle socket 8, and engaging the fulcrum member 9 of theCoupling member 8 in one of the other arcuate slots 10 which will thenallow the handle to be operated in a different position, the arrangementpreferably being such that the handle 14 can operate from asubstantially horizontal position when the jack is in a verticalplacement, and can be used to pump downwardly from this position, towhere the handle 14 can be inclined upwardly at its free end by engagingthe fulcrum member 9 in a lower arcuate slot 10 and can be positioned ata considerable angle if the lowest arcuateslot 10 is engaged.

It will be noted from the drawings that the arcuate slots 10 areradiussed about the piston 6 of the pump,

that is referring to the embodiment shown in FIG. 2, so

arc 'of almost degrees before the fulcrum member.

9 leaves the arcuate slot 10, any of these positions being workable inthat the-fulcrum member 9 will remain in engagement with its particularslot 10 even when turned throughthis relatively substantial arc, thisallowing the jack to be operated from a number of positions and allowingthe actuating handle 14 to be conveniently positioned for any particularoperation.

While the button28 on the release member can be actuated by moving thehandle 14 inwards against it, even when the handle is at an inclinationto the axis of the button, it is preferred to operate it by moving thehandle into substantial axial alignment with the member 30 of therelease mechanism so the handle can push the button 28 inwards in adirect manner to release the valve 27 when the ram is to be lowered.

While in FIG. 3 a three stage pump is shown in which the pistons areinter-engagable to operate singly, that is the piston 40 only can beoperated, or two pistons can act as a pair by bringing down the piston40 on to the piston 41, or as a triple assembly by bringing down thepiston 41 onto the piston 42, it will be realised that a two-stage orfour-stage arrangement on this basis could equally well be achieved.

The difference of course between the arrangement shown in FIG. 3 andthat shown in FIG. 2 is that in FIG. 2 the smaller diameter piston 6operates within the larger diameter piston 7 and the piston 7 operatesin a bore in a cylinder 16, while in the arrangement shown in FIG. 3, astepped bore is used so that it can contain three different sizedpistons each working in a specific part of the main bore.

I claim:

1. A hydraulic jack comprising a base, a housing on said base to form ahydraulic fluid storage, a ram cylinder in said housing, a lifting ramaxially movable in said cylinder and projecting from said cylinder andhousing, a pump cylinder on said base, a duct with a non-return valveconnecting said housing with said pump cylinder to allow flow ofhydraulic fluid from said housing to said cylinder, a duct with anon-return valve connecting said pump cylinder with said ram cylinder toallow flow of hydraulic fluid from said pump cylinder to said ramcylinder, a manually operated return valve to allow hydraulic fluid toreturn from said ram cylinder to said housing, characterized by pistonsof different diameters within said pump cylinder selectively operable byan actuating lever engaging a coupling member connected between saidpistons and said housing, whereby a larger diameter piston can beactuated for quicker relatively lower pressure lifting of the said ram,or a smaller diameter piston can be actuated for slower relativelyhigher pressure lifting of the said ram, and wherein the said actuatinglever can move axially in said coupling member, said coupling memberbeing connected to said smaller diameter piston, and having a fulcrummember engaging one of a series of spaced slots disposed on said housingto allow the said fulcrum member to selectively engage any one slot tovary the relative operating position of the said lever.

2. A hydraulic jack according to claim 1 wherein the smaller diameterpiston operates in a bore of the larger diameter piston which in turnoperates in said pump cylinder, a spring to urge said larger diameterpiston against a stop in a retracted position in said cylinder, thecoupling member between said smaller diameter piston and said actuatinglever allowing the said smaller diameter piston to be reciprocated inthe bore of the said larger diameter piston to act as a relatively highpressure pump, said bore opening into said pump cylinder, and stop meansbetween said larger diameter piston and said smaller diameter pistonwhereby when the stroke of said lever is increased the said smallerdiameter piston carries the said larger diameter piston with it to causethe combined piston area to act as a relatively greater output pump formore rapid ram advancement.

3. A hydraulic jack according to claim 1 wherein the smaller diameterpiston operates in a bore in the said pump cylinder and is connected bya coupling connection to said actuating lever and said large diameterpiston operates in a bore in the said pump cylinder adjacent to the boreof the smaller diameter piston, an axial aperture through said largerdiameter piston, a closure member on said smaller diameter piston toclose said aperture when said smaller piston is moved to contact saidlarger diameter piston, and a spring to urge the larger diameter pistoninto that end of the larger diameter bore which is adjacent the smallerdiameter piston, whereby as the smaller diameter piston is reciprocatedin its bore a relatively high pressure pumping action results throughthe axial aperture of the larger diameter piston into the bore of thepump cylinder, but when the stroke of the smaller diameter piston isextended the smaller diameter piston engages the larger diameter pistonand seals the axial aperture through the larger diameter piston wherebythe larger diameter piston is then moved by the smaller diameter pistonagainst the pressure of the said spring to act as a relatively greateroutput pump for more rapid ram advancement.

4. A hydraulic pump according to claim 3 characterized by at least oneintermediate piston between said smaller diameter piston and said largerdiameter piston disposed in a bore of intermediate diameter, saidintermediate piston having an axial aperture through it with a seatingto engage the axial aperture of the said larger diameter piston, aspring to urge the intermediate piston to that end of the intermediatebore which is adjacent the bore of the smaller diameter piston, saidlast defined spring exerting a lesser force than the said spring whichurges the larger diameter piston to the end of its bore, whereby whenthe smaller diameter piston movement is extended to engage theintermediate piston and reciprocate it, the aperture of the intermediatepiston is closed and the intermediate piston displaces hydraulic fluidthrough the aperture through the larger diameter piston to act as anintermediate output pump for an intermediate rate of advancement of thesaid ram, but when the smaller diameter piston and the intermediatepiston are further extended in their reciprocation the intermediatepiston engages the larger diameter piston to make the aperture of thelarger diameter piston coextensive with the aperture of the intermediatepiston to cause the larger diameter piston to act as a relativelygreater output pump for more rapid ram advancement.

5. A hydraulic jack according to claim 1 wherein said hydraulic fluidreturn valve is actuated from an axially movable button on said housingin line with the said operating lever when engaged in said couplingmember, whereby when said lever is moved to contact and depress saidbutton, the said return valve is actuated to allow return of thehydraulic fluid from the ram cylinder to the housing.

6. A hydraulic jack according to claim 5 wherein the said lever has theend which engages the socket of the said coupling memberscrew threaded,and the coupling member has a member projecting into said socket toengage said screw thread, whereby when the said lever is rotated itmoves axially through the said socket to engage and depress the saidbutton.

7. A hydraulic jack according to claim 1 wherein the coupling member hasa slot engaging a pin on the smaller piston, the slots in the housingbeing arcuate about the axis of the piston to allow orientation of thesaid lever about said piston axis.

8. A hydraulic jack according to claim 1 wherein the said duct whichconnects the housing with the pump cylinder opens into said housingthrough a flexible tube disposed in said housing and having a weight onits free end which is the intake end of the tube, whereby the intake endof the tube and hydraulic fluid in said housing are both positioned inthe housing under the influence of gravity to allow hydraulic fluid tobe drawn into said pump cylinder irrespective of the orientation of thesaid jack.

1. A hydraulic jack comprising a base, a housing on said base to form ahydraulic fluid storage, a ram cylinder in said housing, a lifting ramaxially movable in said cylinder and projecting from said cylinder andhousing, a pump cylinder on said base, a duct with a non-return valveconnecting said housing with said pump cylinder to allow flow ofhydraulic fluid from said housing to said cylinder, a duct with anon-return valve connecting said pump cylinder with said ram cylinder toallow flow of hydraulic fluid from said pump cylinder to said ramcylinder, a manually operated return valve to allow hydraulic fluid toreturn from said ram cylinder to said housing, characterized by pistonsof different diameters within said pump cylinder selectively operable byan actuating lever engaging a coupling member connected between saidpistons and said housing, whereby a larger diameter piston can beactuated for quicker relatively lower pressure lifting of the said ram,or a smaller diameter piston can be actuated for slower relativelyhigher pressure lifting of the said ram, and wherein the said actuatinglever can move axially in said coupling member, said coupling memberbeing connected to said smaller diameter piston, and having a fulcrummember engaging one of a series of spaced slots disposed on said housingto allow the said fulcrum member to selectively engage any one slot tovary the relative operating position of the said lever.
 2. A hydraulicjack according to claim 1 wherein the smaller diameter piston operatesin a bore of the larger diameter piston which in turn operates in saidpump cylinder, a spring to urge said larger diameter piston against astop in a retracted position in said cylinder, the coupling memberbetween said smaller diameter piston and said actuating lever allowingthe said smaller diameter piston to be reciprocated in the bore of thesaid larger diameter piston to act as a relatively high pressure pump,said bore opening into said pump cylinder, and stop means between saidlarger diameter piston and said smaller diameter piston whereby when thestroke of said lever is increased the said smaller diameter pistoncarries the said larger diameter piston with it to cause the combinedpiston area to act as a relatively greater output pump for more rapidram advancement.
 3. A hydraulic jack according to claim 1 wherein thesmaller diameter piston operates in a bore in the said pump cylinder andis connected by a coupling connection to said actuating lever and saidlarge diameter piston operates in a bore in the said pump cylinderadjacent to the bore of the smaller diameter piston, an axial aperturethrough said larger diameter piston, a closure member on said smallerdiameter piston to close said aperture when said smaller piston is movedto contact said larger diameter piston, and a spring to urge the largerdiameter piston into that end of the larger diameter bore which isadjacent the smaller diameter piston, whereby as the smaller diameterpiston is reciprocated in its bore a relatively high pressure pumpingaction results through the axial aperture of the larger diameter pistoninto the bore of the pump cylinder, but when the stroke of the smallerdiameter piston is extended the smaller diameter piston engages thelarger diameter piston and seals the axial aperture through the largerdiameter piston whereby the larger diameter piston is then moved by thesmaller diameter piston against the pressure of the said spring to actas a relatively greater output pump for more rapid ram advancement.
 4. Ahydraulic pump according to claim 3 characterized by at least oneintermediate piston between said smaller diameter piston and said largerdiameter piston disposed in a bore of intermediate diameter, saidintermediate piston having an axial aperture through it with a seatingto engage the axial aperture of the said larger diameter piston, aspring to urge the intermediate piston to that end of the intermediatebore which is adjacent the bore of the smaller diameter piston, saidlast defined spring exerting a lesser force than the said spring whichurges the larger diameter piston to the end of its bore, whereby whenthe smaller diameter piston movement is extended to engage theintermediate piston and reciprocate it, the aperture of the intermediatepiston is closed and the intermediate piston displaces hydraulic fluidthrough the aperture through the larger diameter piston to act as anintermediate output pump for an intermediate rate of advancement of thesaid ram, but when the smaller diameter piston and the intermediatepiston are further extended in their reciprocation the intermediatepiston engages the larger diameter piston to make the aperture of thelarger diameter piston coextensive with the aperture of the intermediatepiston to cause the larger diameter piston to act as a relativelygreater output pump for more rapid ram advancement.
 5. A hydraulic jackaccording to claim 1 wherein said hydraulic fluid return valve isactuated from an axially movable button on said housing in line with thesaid operating lever when engaged in said coupling member, whereby whensaid lever is moved to contact and depress said button, the said returnvalve is actuated to allow return of the hydraulic fluid from the ramcylinder to the housing.
 6. A hydraulic jack according to claim 5wherein the said lever has the end which engages the socket of the saidcoupling member screw threaded, and the coupling member has a memberprojecting into said socket to engage said screw thread, whereby whenthe said lever is rotated it moves axially through the said socket toengage and depress the said button.
 7. A hydraulic jack according toclaim 1 wherein the coupling member has a slot engaging a pin on thesmaller piston, the slots in the housing being arcuate about the axis ofthe piston to allow orientation of the said lever about said pistonaxis.
 8. A hydraulic jack according to claim 1 wherein the said ductwhich connects the housing with the pump cylinder opens into saidhousing through a flexible tube disposed in said housing and having aweight on its free end which is the intake end of the tube, whereby theintake end of the tube and hydraulic fluid in said housing are bothpositioned in the housing under the influence of gravity to allowhydraulic fluid to be drawn into said pump cylinder irrespective of theorientation of the said jack.